DE102017223892A1 - Process for the preparation of a functionalized semiconductor or conductor material and its use - Google Patents

Abstract

The invention relates to a method for producing functionalized semiconductor or conductor material from a layered base material by electrolytic exfoliation, in an electrolytic cell, comprising at least one electrode pair of first and second electrodes, and an aqueous and / or alcoholic electrolyte solution containing sulfuric acid and / or at least one salt selected from sulfate and / or hydrogen sulfate and / or perchlorate and / or persulfate salt.

Description

The invention relates to a method for producing and functionalizing a semiconductor or conductor material by electrolytic exfoliation of a base material and in-situ functionalization of the layers and / or monolayers formed thereby.

State of the art

The isolation of individual layers of two-dimensionally structured or layered semiconductor or conductor materials has been of interest for several years, not least because the use of these materials in electronic components leads to enormous increases in performance and efficient applications.

An example of such an isolated layer of a two-dimensionally structured or layered material is graphene, which is a monolayer, that is to say a single layer of graphite, only one atomic layer thick, of a naturally occurring form of the carbon in pure form. Graphene also refers to material in which some of these monolayers are stacked on top of each other.

Graphene can be understood as a two-dimensional network of contiguous benzene rings, which i.a. has an enormous electrical conductivity. Its electronic, thermal, optical and mechanical properties make it of great use in many fields of technology. Methods for the scalable and efficient production of high-quality conductor and semiconductor materials that can be processed as far as possible from the solution, such as graphene, are therefore the subject of intensive research.

The production of, for example, graphene is carried out under sometimes difficult process conditions, since work is carried out on a laboratory scale with high-boiling solvents such as DMF and NMP. An upscaling to an industrial scale is thus extremely problematic and hitherto prevented the large-scale production and application of this material.

Another challenge is the storage of freshly prepared graphene, as this is difficult to redispersible after drying and the processability of the material monolayers or oligolayers is enormously difficult.

One of the most important, but hitherto little-used technology for the production of monolayers or thin layers of conductor materials such as graphene is the electrolytic exfoliation of two-dimensional, layered structured base material, such as graphite.

The exfoliation of graphite to produce graphene, for example in the form of flakes or flakes, represents a cost-effective and reliable strategy for its recovery.

Graphene layers as flakes have already been successfully made of graphite as a base material in the solid state (see, for example, i) KS Novoselov, AK Geim, SV Morozov, D.Jiang, Y. Zhang, SV Dubonos, IV Grigorieva, AA Firsov, Science 2004, 306, 666-669 ; ii) Leon, M. Quintana, MA Herrero, JLG Fierro, A. d. I. Hoz, M. Prato, E. Vazquez, Chem. Commun. 2011, 47, 10936-10938 ) or in the liquid phase (see for example i) ZY Xia, S. Pezzini, E. Treossi, G. Giambastiani, F. Corticelli, V. Morandi, A. Zanelli, V. Bellani, V. Palermo, Adv. Funct. Mater. 2013, 23, 4684-4693 ; b) A. Ciesielski, P. Samori, Chem. Soc. Rev. 2014, 43, 381-398 .) isolated.

Graphene has also been successfully prepared by the reduction of graphene oxide, which can be prepared, for example, by the so-called Hummers method (W.S.Hummers et al., J. Am. Chem. Soc. 1958, 80, 6, 1339).

Graphene oxide is highly dispersible in a variety of solvents, particularly water, which greatly facilitates the implementation of a larger scale application. It is also redispersible after complete drying.

However, disadvantageous in the reduction methods are always oxide groups and other defects, such as holes or not six-fold rings within the material. These structural defects lead to severe limitations of the electronic and thermal properties of graphene oxide Graphene ( C. Gomez-Navarro, RT Weitz, AM Bittner, M. Scolari, A. Mews, M. Burghard, K. Kern, Nano Lett. 2007, 7, 3499-3503 ).

The so-called liquid-phase exfoliation of graphite uses purely physical shear forces, especially organic solvents, and allows for the production of graphene with significantly fewer defects (see, for example, a) F. Bonaccorso, A. Bartolotta, JN Coleman, C. Backes, Adv. Mater. 2016, 28, 6136-6166 ; b) A. Ciesielski, S.Harry, M.I. Gemayel, H. Yang, J. Clough, G. Melinte, M. Gobbi, E. Orgiu, MV Nardi, G. Ligorio, V. Palermo, N. Koch, O. Ersen, C. Casiraghi, P. Samori, Angew. Chem. Int. Ed. 2014, 53, 10355-10361 ). However, disadvantageous results are that only low yields of exfoliated graphene and very small lateral layer sizes ( JN Coleman, Acc. Chem. Res. 2013, 46, 14-22 ).

In addition, the small flakes of material tend to re-aggregate (stack) after exfoliation. The use of surfactants or other additives to prevent this effect is therefore inevitable. However, these additives are difficult to remove and significantly reduce the conductivity of the product.

Anodic exfoliation has recently become a very promising method for producing high quality graphene on a large scale, at low cost and in aqueous solution.

The two-dimensionally structured base material can either be used as an anode in aqueous solutions of ionic liquids (see, for example, US Pat X. Wang, PF Fulvio, GA Baker, GM Veith, RR Unocic, SM Mahurin, M. Chi, S. Dai, Chem. Commun. 2010, 46, 4487-4489 ) or mineral acids (see, for example, a) KS Rao, J. Sentilnathan, H.-W. Cho, J.-J. Wu, M. Yoshimura, Adv. Funct. Mater. 2015, 25,298-305 ; b) K. Parvez, R. Li, SR Puniredd, Y. Hernandez, F. Hinkel, S. Wang, X. Feng, K. Müllen, ACS Nano 2013, 7, 3598-3606 ) or inorganic salts (eg (a) K. Parvez, Z.S. Wu, R. Li, X. Liu, R. Graf, X. Feng, K. Müllen, J. Am. Chem. Soc. 2014, 136, 6083-6091 ; b) S. Yang, S. Brüller, Z.-S. Wu, Z. Liu, K. Parvez, R. Dong, F. Richard, P. Samorl, X. Feng, K. Müllen, J. Am. Chem. Soc. 2015, 137, 13927-13932 ). Under the influence of the electric current, electrons are split off from the two-dimensionally structured base material, eg graphite, and leave a positive charge at the anode. The anions of the electrolyte can then be easily pushed between the individual layers of the base material, such as graphite, and split off.

However, the graphene produced in this way disadvantageously contains high proportions of oxygen groups. This is due to oxygen radicals such as HO · or O ·, which are formed during the manufacturing process by the splitting of water and add to the graphene layers (see KS Rao, J. Sentilnathan, H.-W. Cho, J.-J. Wu, M. Yoshimura, Adv. Funct. Mater. 2015, 25, 298-305 ).

Another problem is the implementation of the method in high-boiling solvents such as DMF or NMP. In addition, the exfoliated layers cling together after drying and it is difficult to redisperse them.

One way to increase the dispersibility of graphene layers is to functionalize graphene sheets with small molecules or polymers.

Previous work has focused on the cathodic exfoliation of graphite in organic solvents and the concurrent in situ functionalization of the graphene layers with diazonium salts (see, inter alia, (a) Ejigu, A. Kinloch, IA; Dryfe, RAW, Single Stage Simultaneous Electrochemical Exfoliation and Functionalization of Graphenes ACS Applied Materials & Interfaces 2017, 9 (1), 710-721; (b) Zhong, YL; Swager, TM, Enhanced Electrochemical Expansion of Graphite for In Situ Electrochemical Functionalization. Journal of the American Chemical Society 2012, 134 (43), 17896-17899; (c) Ossonon, BD; Belanger, D., Functionalization of graphene sheets by the diazonium chemistry during electrochemical exfoliation of graphite., Carbon 2017, 111, 83-93.)
The diazonium salts generate free radicals and functionalize the surface through a reduction reaction at the cathode.

Further publications are concerned with the anodic exfoliation of graphite using various organic salts as electrolyte such as phytic acid ( Feng, X .; Wang, X .; Cai, W .; Qiu, S .; Hu, Y .; Liew, KM, Studies on Synthesis of Electrochemically Exfoliated Functionalized Graphene and Polylactic Acid / Ferric Phytates Functionalized Graphene Nanocomposites as New Fire Hazard Suppression Materials. ACS Applied Materials & Interfaces 2016, 8 (38), 25552-25562) , Hex (4-carboxyphenoxy) cyclotriphosphazene ( Cai, W .; Feng, X .; Wang, B .; Hu, W .; Yuan, B .; Hong, N .; Hu, Y., A novel strategy for a simultaneous electrochemical preparation and functionalization of a multifunctional flame retardant. Chemical Engineering Journal 2017, 316, 514-524 ), Tetracyanoquinodimethane ( Khanra, P .; Lee, C.-N .; Kuila, T .; Kim, NH; Park, MJ; Lee, JH, 7,7,8,8-Tetracyanoquinodimethane Assessed one-step electrochemical exfoliation of graphite and its performance as an electrode material. Nanoscale 2014, 6 (9), 4864-4873 .), 9-Anthracene carboxylic acid ( Khanra, P .; Kuila, T .; Bae, SH; Kim, NH; Lee, JH, Electrochemically exfoliated graphene using 9-anthracene carboxylic acid for supercapacitor application. Journal of Materials Chemistry 2012, 22 (46), 24403-24410 ), Tetrasodium tetrasulfonic acid ( Mensing, JP; Kerdcharoen, T .; Sriprachuabwong, C .; Wisitsoraat, A .; Phokharatkul, D .; Lomas, T .; Tuantranont, A., Facile preparation of graphene-metal phthalocyanine hybrid material by electrolytic exfoliation. Journal of Materials Chemistry 2012, 22 (33), 17094-17099 ), or organic sodium sulfonates ( Munuera, JM; Paredes, JI; Villar-Rodil, S .; Ayan-Varela, M .; Martinez-Alonso, A .; Tascon, JMD, Electrolytic exfoliation of graphite in water with multifunctional electrolytes: en route to high quality, oxide-free graphene flakes. Nanoscale 2016, 8 (5), 2982-2998 ).

These publications describe the intercalation of the salt between the individual layers of the graphite and the functionalization of the layers by p-p interactions.

The functionalized graphene layers show high I _D / I _G ratios in the RAMAN spectrum. The conductivity of the layers and their dispersibility is not considered.
In some examples, the use of functionalized graphene as electrode material in batteries or supercapacitors is described.
Other publications show the exfoliation of graphite with mixed electrolytes such as ammonium sulfate / ammonia or glycine and ammonia. Also, Na ₂ S ₂ O ₃ / H ₂ SO ₄ systems and potassium halides were used to dope the graph with heteroatoms or halogens.

Chen et al. (Chen, CH et al., Nanoscale, 2015, 7, 15362-15373) published a method for producing highly crystalline graphene by electrolytic exfoliation in 0.65 M sulfuric acid with the addition of melamine in high concentrations of 10 to 200 g / 100 ml electrolyte solution. At voltages of 20 V, graphene layers are exfoliated from the graphite electrode with a periodic reversal of the polarity with a period of 10 minutes and afflicted with melamine molecules. These in-situ applied protective layers prevent further oxidation of the graphene layer and thus lead to larger graphene crystallites. The remaining melamine is then washed off the collected graphene with water, which after drying shows a high C / O ratio of 26.17, that is, a low defect density of oxygen defects. The authors assume that there is no covalent functionalization of the graphene platelets. The graphene thus prepared is readily dispersible in DMF or NMP. Specified is u.a. the use of a dispersion of graphene in DMF for processing on quartz substrates.

Another possibility for producing functionalized graphene is the use of ionic liquids, ie salts which are liquid at temperatures below 100 ° C., without the salt being dissolved in a solvent such as water.
A publication by Liu et al. (Adv. Funct., Mater., 2008, 18, 1518-1525) describes the electrolytic exfoliation of graphite in an aqueous electrolyte solution containing ionic liquids. The cations of the ionic liquids intercalate between the individual layers of the graphite and thus drive them apart. In this case, an imidazolium hexafluorophosphate was used as the ionic liquid. XPS measurements revealed that the two nitrogen atoms of the imidazolium group interact with the surface of the graphene and thus bind the salt to the graphene. The thus functionalized graphene is not dispersible in water but in aprotic solvents such as DMF or NMP.

Ouhib et al published a method for producing functionalized graphene from a few layers in 2014 (Ouhib et al., J. Mater. Chem. A, 2014, 2, 15298). High order pyrolytic graphite (HOPG) was introduced as a cathode into an electrolytic cell with an electrolyte containing an ammonium salt and vinyl monomers, and exfoliated graphene layers. In parallel with this, the electropolymerization of the vinyl monomers took place, with a chemisorbed polymer layer forming around the graphene layers. Disadvantageously, the electrolysis again took place in anhydrous, high-boiling organic solvents such as DMF and the exfoliation takes place only with the aid of an ultrasound treatment. The cathodic exfoliation also ensures that no monolayers of graphene can be formed, but rather are graphite nanoplatelets with> 20 to 50 atomic layers, as in the Raman spectrum of the sample in 2 the publication can be seen. Few-layer graphene, in contrast to graphite, would exhibit a symmetric 2D peak with no shoulder at -2700 cm ^-1 in the spectrum, but this is in 2 clearly.

One way to functionalize the exfoliated layers of conductor or semiconductor materials, such as graphene, to protect them from the addition of hydroxyl radicals while increasing the dispersibility of the layers in environmentally friendly solvents without the addition of surfactant additives is not known the technique is not known yet.

Object of the invention to provide a process for the production of functionalized semiconductor or conductor materials by electrolytic exfoliation in environmentally friendly and industrially easy to use solvents while functionalizing the monolayers or thin layers of the material for better dispersibility and ease of processing.

1. a) Inkontaktbringen der Elektroden mit der Elektrolytlösung,
2. b) Elektrolytische Exfolierung des Grundmaterials, beispielsweise in Form von Partikeln aus funktionalisiertem Leiter- oder Halbleitermaterial, durch Anlegen einer Spannung zwischen erster und zweiter Elektrode,
3. c) Abtrennen des funktionalisierten Halbleiter- oder Leitermaterials von der Elektrolytlösung,

wobei mindestens die erste der Elektroden des Elektrodenpaares das geschichtet strukturierte, kohlenstoffbasierte Grundmaterial enthält, wobei die erste Elektrode als Anode geschaltet ist, wobei der Elektrolytlösung vor und/oder, während und/oder unmittelbar nach der elektrolytischen Exfolierung mindestens eine organische Verbindung zugegeben wird, wobei die organische Verbindung ausgewählt ist aus

1. i) Anodisch oxidierbaren, organischen Molekülen, enthaltend mindestens eine Alkohol- und/oder mindestens eine Amino- und/oder mindestens eine Carboxylgruppe und/oder,
2. ii) organischen Molekülen enthaltend mindestens eine Isocyanat- und/oder mindestens eine Halogenid- und/oder mindestens eine Epoxid- und/oder mindestens eine Diazonium- und/oder mindestens eine Peroxid- und/oder mindestens eine Azidgruppe und/oder cyclische Esther und/oder cyclische Amide und/oder,
3. iii) und/oderPräkursoren oder Monomeren elektrisch leitender Polymere und/oder
4. iv) frei radikal polymerisierbaren, wasserlöslichen Vinyl-Monomeren, welche in ihrer Struktur wenigstens eine Aminogruppe (bspw. Isopropylacrylamid) und/oder eine anionische funktionelle Gruppe (bspw. SO₃ ^-, NO₂ ^-, CO₂ ^-2, PO₃ ^-3, O^-) aufweisen bspw. Styrensulfonat).

The object is achieved by a method for producing functionalized semiconductor or conductor materials from a layered base material by electrolytic exfoliation, in an electrolytic cell comprising at least one electrode pair of first and second electrodes, and an aqueous and / or alcoholic electrolyte solution containing sulfuric acid and / or at least one sulfate and / or hydrogen sulfate salt and / or a perchlorate and / or a persulfate,
with the steps:

1. a) contacting the electrodes with the electrolyte solution,
2. b) electrolytic exfoliation of the base material, for example in the form of particles of functionalized conductor or semiconductor material, by applying a voltage between the first and second electrodes,
3. c) separating the functionalized semiconductor or conductor material from the electrolyte solution,

wherein at least the first of the electrodes of the electrode pair contains the layered carbon-based base material, wherein the first electrode is connected as an anode, wherein at least one organic compound is added to the electrolyte solution before and / or during and / or immediately after the electrolytic exfoliation the organic compound is selected from

1. i) anodically oxidizable organic molecules containing at least one alcohol and / or at least one amino and / or at least one carboxyl group and / or
2. ii) organic molecules containing at least one isocyanate and / or at least one halide and / or at least one epoxide and / or at least one diazonium and / or at least one peroxide and / or at least one azide group and / or cyclic esters and / or or cyclic amides and / or
3. iii) and / or precursors or monomers of electrically conductive polymers and / or
4. iv) free radically polymerizable water-soluble vinyl monomers, which in its structure at least one amino group (for example isopropyl) and / or an anionic functional group (e.g. SO ₃ ^-.., NO ₂ ^-, CO ₂ ^-2, PO ₃ ^-3 , O ^- ) have, for example, styrene sulfonate).

For the purposes of the invention, a conductor or semiconductor material is an electrically conductive material having a highly ordered, layered structure, consisting of a monolayer of the material or of a plurality of superimposed layers of the material. The semiconductor material has a specific bandgap formed from the energy difference between the valence band and conduction band.

For the purposes of the invention, "functionalized" means that the material is coated with functional groups or polymer chains which adhere to the surface of the material by chemical reaction or at least chemisorption.

In one embodiment, the semiconductor or conductor material is a carbon-based material, that is, its backbone mainly contains carbon.

In one embodiment, the functionalized semiconductor or conductor material is in the form of nanoscale to micrometer sized particles.

In one embodiment, the semiconductor or conductor material is selected from graphene, graphene derivatives, carbon-based semiconductor or ladder polymers, and / or layered chalcogenides of the general formula MQ ₂ , where M = Ti, Zr, Hf, V, Nb, Ta , Mo or W and where Q = O, S, Se or Te.

In one embodiment, the two-dimensionally layered structured base material is selected from semiconductive or conductive carbon modifications, carbon-based semiconductor or conductor polymers in the form of two-dimensionally structured base material and / or layered chalcogenides.

In one embodiment, the semiconductive or conductive carbon modifications selected from graphite, non-graphitic carbon, carbon nanofoam, glassy carbon, carbon black, activated carbon, carbon fibers, tar and pitch, and derivatives thereof.

Graphite can be naturally occurring or synthetically produced graphite.

The exfoliation of the semiconductor or conductor material from or from the two-dimensional, layered structured base material takes place electrolytically in an electrolysis cell which contains at least one pair of electrodes. A pair of electrodes comprises a first electrode E1 and a second electrode E2 ,

In one embodiment, at least the first electrode E1 the base material in the form of flakes, powders, fibers, films, pieces, pastes or a mixture of these. The electrode may also be a single flake of the base material, or several of these flakes, which are either pressed against each other or interconnected by a conductive material.

According to the invention, the electrode E1 switched during the exfoliation as an anode.

In an embodiment, the second electrode comprises a metal. In one embodiment, the metal is a noble metal selected from Cu, Au, Ag, Pt, Pd.

In another embodiment, the metal is a non-noble metal or alloy selected from Fe, steel, Al, Pb, brass, Ti, Zn, Sn, Ni, Hg, Mg.

In one embodiment, the metal-containing electrode is connected as a cathode during exfoliation.

In an embodiment, the second electrode comprises a non-elemental metallic conductive material. In one embodiment, the non-elemental metallic material is selected from graphite, carbon and / or conductive polymers.

In one embodiment, the non-elemental metal electrode is connected as a cathode during exfoliation.

According to the invention, the electrolyte solution is an aqueous and / or alcoholic solution

In one embodiment, the solution is aqueous and alcoholic, that is, it contains a mixture of water and alcohol.

In one embodiment, the ratio of water / alcohol is 100: 0 to 0: 100, preferably 99: 1 to 1:99, more preferably 20:80 to 80:20.

In one embodiment, the alcohol comprises only one alcoholic component. In another embodiment, the alcohol comprises a plurality of different alcoholic components.

In one embodiment, the alcohol is selected from ethanol and / or ethylene glycol.

According to the invention, the electrolyte solution contains sulfuric acid and / or at least one salt selected from sulfate and / or hydrogen sulfate and / or perchlorate and / or persulfate salt.

For the purposes of the invention, the salt comprises either only one salt component or a mixture of several salt components.

In one embodiment, the salt is an inorganic salt.

In one embodiment, the inorganic salt is selected from (NH ₄ ) ₂ SO ₄ and / or K ₂ SO ₄ and / or Na ₂ SO ₄ and / or KHSO 4 and / or NaHSO ₄ and / or a persulfate.

In one embodiment, the salt is an organic salt. In one embodiment, the organic salt is selected from tetraalkylammonium sulfates and / or tetraalkylammonium hydrogen sulfates.

The cation of the salt thus corresponds to the general formula NR ₄ ⁺ , where R = H and / or C 1 to C 5 alkyl, where all Rs may be the same or different.
In step a), the electrodes are brought into contact with the electrolyte solution.

In one embodiment, the electrodes are immersed in the electrolyte solution. In another embodiment, the electrolyte solution is added to the electrodes in the electrolytic cell.

In step b), the electrolytic exfoliation of the base material by applying a voltage between the first and second electrode.

In one embodiment, the voltage is 1 to 30 V, preferably 5 to 15 V, particularly preferably 8 to 12 V, in particular 10 V.

According to the invention contains at least the first electrode E1 the two-dimensionally structured, stratified base material. This electrode E1 is switched as an anode. By applying a voltage, the formation of oxygen-containing radicals, such as HO or O, initially takes place in the anode region and attacks the boundary surfaces or intrinsic defects of the base material and adds thereto, forming oxides of the base material. At the same time, the marginal layers of the base material are forced apart so that the anions of the electrolyte, that is, sulfate and / or hydrogen sulfate ions, can push far apart and expand the spacing of the individual layers of the base material.

The intercalation of the anions of the electrolyte leads to the widening of the distance between the layers, to such an extent that the intermolecular forces can be overcome so that individual layers separate from the electrode. Thus, the exfoliation of a monolayer or multiple layer or a thin layer of the base material from the electrode occurs.

These monolayers or multiple layers or layers of the base material are coated or functionalized in situ with the organic compound contained or added in the electrolytic solution.

According to the invention, at least one organic compound is added to the electrolyte solution before and / or during and / or after the electrolytic exfoliation.

1. i) Anodisch oxidierbaren, organischen Molekülen, enthaltend mindestens eine Alkohol- und/oder mindestens eine Amino- und/oder mindestens eine Carboxylgruppe und/oder,
2. ii) organischen Molekülen enthaltend mindestens eine Isocyanat- und/oder mindestens eine Halogenid- und/oder mindestens eine Epoxid- und/oder mindestens eine Diazonium- und/oder mindestens eine Peroxid- und/oder mindestens eine Azidgruppe und/oder cyclische Esther und/oder cyclische Amide und/oder,
3. iii) und/oderPräkursoren oder Monomeren elektrisch leitender Polymere und/oder
4. iv) frei radikal polymerisierbaren, wasserlöslichen Vinyl-Monomeren, welche in ihrer Struktur mindestens eine Aminogruppe (bspw. Isopropylacrylamid) und/oder mindestens eine anionische funktionelle Gruppe (bspw. SO₃ ^-, NO₂ ^-, CO₂ ^-2, PO₃ ^-3, O^-) aufweisen bspw. Styrensulfonat).

According to the invention, the at least one organic compound is selected from

1. i) anodically oxidizable organic molecules containing at least one alcohol and / or at least one amino and / or at least one carboxyl group and / or
2. ii) organic molecules containing at least one isocyanate and / or at least one halide and / or at least one epoxide and / or at least one diazonium and / or at least one peroxide and / or at least one azide group and / or cyclic esters and / or or cyclic amides and / or
3. iii) and / or precursors or monomers of electrically conductive polymers and / or
4. iv) free-radically polymerizable, water-soluble vinyl monomers which have in their structure at least one amino group (for example isopropylacrylamide) and / or at least one anionic functional group (for example SO ₃ ^- , NO ₂ ^- , CO ₂ ^-2 , PO ₃ ^{- 3} , O ^- ) have, for example, styrene sulfonate).

The variants i) to iv) can be combined as desired.

According to the invention, the at least one organic compound in variant i) is selected from anodic oxidizable, organic molecules containing at least one alcohol and / or at least one amino and / or at least one carboxyl group (see Table 1)

In aqueous solution, the alcohol and / or amino and / or carboxyl groups are in equilibrium with their deprotonated, ie anionic form.

By applying a voltage between the electrodes E1 and E2 The anodically oxidizable, organic molecules migrate / diffuse into the anode region due to their partially negative charge and are electrolytically oxidized there, that is, an electron is abstracted. Radicals form according to the following equations:

These radicals react with the surface of the semiconductor and / or conductor material and functionalize it by forming a coating of molecules.

In one embodiment, the organic molecules are selected from primary and / or secondary amines and / or carboxylic acids and / or alcohols.

According to the invention, the at least one organic compound in variant ii) is selected from organic molecules containing at least one isocyanate and / or at least one halide and / or at least one epoxide and / or at least one diazonium and / or at least one peroxide and / or or at least one azide group and / or cyclic esters and / or cyclic amides

Depending on the functionality of the molecules, the addition of the organic compound in variant i) preferably takes place before and / or during and / or immediately after the electrolytic exfoliation. Table 1 Functional group Time of addition of the molecule Notes / examples / functionalization mechanisms "R-OH alcohols" before / during and / or after eg: iso-butanol R: aromatic and aliphatic before / during eg: valeric acid, benzoic acid, R - COOH and or sodium cholate R - COO- to R - COX "Carboxylic acids / carboxylates" R: aromatic and aliphatic

According to the invention, the organic compound in variant ii) is selected from organic molecules containing at least one isocyanate and / or at least one halide and / or at least one epoxide and / or at least one diazonium and / or at least one peroxide and / or at least an azide group and / or cyclic esters and / or cyclic amides

In one embodiment, the addition of the organic compound in variant ii) takes place immediately after the electrolytic exfoliation of the semiconductor or conductor material.

Table 2 lists the substance groups of, organic compounds according to variant ii), the time of their addition and selected examples of the substance groups (see Table 2).

„Epoxide“ nach R: aromatisch und aliphatisch

„Diazonium“ nach R: aromatisch und aliphatisch

„Peroxide“ nach R: aromatisch

NaN₃, nach R-N₃ R: aromatisch und aliphatisch „Azide“

Kationische Ringöffnungspolymerisation „Zyklische Ester“

„Zyklische Amide“ nach R: aliphatic The radicals R are, in general, organic compounds which each have at least one of the functional groups given in the table. The preferred embodiment of the radicals R (aromatic and / or aliphatic) is given in Table 1 in the column "functional group". Table 2 Functional group Time of addition of the molecule Notes / examples / functionalization mechanisms R-CNH to "Isocyanates" R: aromatic and aliphatic to R - Hal "Halides" R: aromatic and aliphatic before / during Preferred primary amines, eg melamine, and or Butylamine, t-octylamine " to R-NH ₂ R - NHR amines " R: aromatic and aliphatic

"Epoxides" to R: aromatic and aliphatic

"Diazonium" to R: aromatic and aliphatic

"Peroxide" to R: aromatic

NaN ₃ , to RN ₃ R: aromatic and aliphatic "Azides"

Cationic ring-opening polymerization "Cyclic esters"

"Cyclic Amides" to R: aliphatic

According to the invention, the organic compound in variant iii) is selected from anodically or oxidatively polymerizable precursors or monomers of electrically conductive polymers.

In one embodiment, the precursors or monomers of the electrically conductive polymers in variant iii) are selected from aromatic amines, aniline, pyrrole, thiophene and / or derivatives thereof

In one embodiment, the electrically conductive polymers in variant iii) are selected from substituted and / or unsubstituted polyanilines, polypyrroles, and / or polythiophenes.

In one embodiment, a substituted polyaniline is sulfonated polyaniline.

The functionalization of the conductor or semiconductor material is carried out with the compounds according to variant iii) by oxidative polymerization.

As in the case of functionalization with small organic anodic oxidizable molecules, the anions of the electrolyte first intercalate between the individual layers of the base material during electrolysis and drive them apart until they split off. In parallel, the monomers or precursors of the electrically conductive polymers are anodically oxidized, that is, an electron is abstracted to form radical cations. These react with the surface of the exfoliated semiconductor or conductor material and continue to polymerize there. This forms a polymer coating on the mono- and / or multiple layers or layers of the conductor material and functionalizes them.

In one embodiment, the addition of anodically or oxidatively polymerizable precursors or monomers of electrically conductive polymers takes place immediately after the electrochemical exfoliation of semiconductor or conductor material.

The proposed mechanism for functionalization immediately or directly after exfoliation is in 14 shown. The process of electrochemical exfoliation contains free radicals on the surface of the EC, which are stabilized by the extensive network of conjugated electrons. These free radicals and anions can be used as starting points for free-radical and oxidative polymerization reactions to covalently functionalize the graphene surface. Another possible mechanism is the activation of oxygen-containing groups (in epoxide) on the graphene surface by electrochemical exfoliation.

According to the invention, the organic compound in variant iv) is selected from free-radically polymerizable, water-soluble vinyl monomers which have in their structure at least one amino group and / or one anionic functional group (Table 3).

vor/während und/oder nach Polymerisation (frei radikalisch , kationisch) z.B.: N-Isopropylacrylamid, „Vinyl-Verbindungen“ Methylenebisacrylamid, Natrium-4- R:aromatic and aliphatic vinylbenzensulfonat In one embodiment, the anionic functional group is selected from SO ₃ ^- , NO ₂ ^- , CO ₂ ^-2 , PO ₃ ^-3 , O ^- (for example, isopropylacrylamide or styrenesulfonate). Table 3 Functional group Time of addition of the molecule Notes / examples / functionalization mechanisms

before / during and / or after Polymerization (free-radical, cationic), for example: N-isopropylacrylamide, "Vinyl compounds" Methylenebisacrylamide, sodium 4- R: aromatic and aliphatic vinylbenzensulfonat

In variant iv) of the process according to the invention, the free radical polymerization of the water-soluble vinyl monomers takes place.

Vinyl monomers would normally polymerize at the cathode based on the vinyl group reduction reaction (anionic polymerization mechanism). For such reactions typically anhydrous organic solvents are used in a protective gas atmosphere in the prior art.

However, when such monomers contain functional groups which oxidize faster than the vinyl group is reduced, or if they anionic groups such as SO ₃ ^-, NO ₂ ^-, CO ₂ ^-, PO ₃ ^- contain, they move to the anode and can be activated by free radicals from water splitting, perform a free radical polymerization (see ).

This type of polymerization is for example for monomers such as isopropylacrylamide and vinyl monomers (see for example containing anionic groups (such as, for example, sodium 4-vinylbenzenesulfonate, successfully performed.

Surprisingly, it was found that the polymerization in the presence of the exfoliated conductor or semiconductor material led to polymer-functionalized conductor or semiconductor material.

In step c) of the method according to the invention, the functionalized semiconductor or conductor material, for example in the form of particles, is separated from the electrolyte solution. The person skilled in separation methods are known.

In one embodiment, the functionalized material is dried after separation.

In one embodiment, the functionalized material is dried and / or dispersed after separation.

The preparation of highly concentrated and stable dispersions is hitherto possible from the prior art only with the use of additives, such as, for example, surfactants. With surfactants almost arbitrarily high filler contents of the dispersions can be adjusted in different solvents or media.

However, surfactants have an adverse effect on interactions with the matrix (for example in polymer composites) and reduce the conductivity and stability of the applied semiconductor or conductor layers, for example in print applications. The surfactants must be subsequently washed out in a complex process or thermally removed. This complicates the processing and is also extremely cost and energy intensive.

Advantageously, the dispersion of the inventively functionalized material is possible not only in organic, anhydrous, but in particular in aqueous solvents without the addition of surfactants.

Advantageously, the dispersion is possible not only in solvents, but also in a wide range of reactants, for example Polymerisationspräkusoren, epoxies, silicones without the use of additives such as surfactants.

The dispersions prepared according to the invention are stable even without the addition of such additives over a long period of time and can be easily processed, which is advantageous, for example, in the coating of substrates with the functionalized conductor or semiconductor material.

In one embodiment, the dispersion is carried out in a solvent selected from water and / or alcohols.

In one embodiment, the solvent is aqueous and alcoholic, that is, it contains a mixture of water and alcohol.

In one embodiment, the volume ratio of water / alcohol is 0: 100 to 100: 0, preferably 99: 1 to 1:99, particularly preferably 80:20 to 20:80.

In one embodiment, the alcohol comprises only one alcoholic component. In another embodiment, the alcohol comprises a plurality of different alcoholic components.

In one embodiment, the alcohol is selected from ethanol and / or ethylene glycol.

In one embodiment, the concentration of the functionalized material in aqueous and / or alcoholic dispersions is 0.1 to 2 g / l, preferably 0.1 to 1 g / l.

Advantageously, dispersions which are substantially more highly concentrated than hitherto known from the prior art can therefore be produced without the use of additives which modify the interfacial tension, for example surfactants.

As a result of the functionalization of the semiconductor or conductor material according to the invention, it is thus possible for the first time to process or process the material, for example on electrodes or substrates, from a wide variety of media.

• - EG-SPANI = Exfoliertes Graphen, mit sulfoniertem Polyanilin funktionalisiert,
• - EG-PANI = Exfoliertes Graphen, mit Polyanilin funktionalisiert,
• - EG-PPy = Exfoliertes Graphen, mit Polypyrrol funktionalisiert,
• - EG-PNIPAM = Exfoliertes Graphen, mit Poly(N-isopropylacrylamid) funktionalisiert,
• - EG-PSS = Exfoliertes Graphen, mit Poly(styrenesulfonat) funktionalisiert,
• - EG-PAM = Exfoliertes Graphen, mit Poly(Methylen-bis-acrylamid) funktionalisiert.

For example, stable dispersions of graphene functionalised according to the invention with polyaniline (EG-PANI) could be produced in high concentrations in water or ethylene glycol. Similarly, the preparation of dispersions of sulfonated polyaniline functionalized graphene (EC-SPANI) in water, ethanol and ethylene glycol. Further examples are listed in Table 4. TABLE 4 Examples of stable dispersions of various materials prepared according to the invention in various media and various concentrations: Entry Product Solvent Stable concentration (mg / mL) 1 EC SPAIN Water 0.4 2 EC SPAIN ethanol 0.5 3 EC SPAIN Ethylene glycol 1 4 EC SPAIN DMF 1 5 EC PANI Water 0.1-0.2 6 EC PANI ethanol 0.3-0.4 7 EC PANI Ethylene glycol 0.5-0.6 8th EC PPy Water 0.1-0.2 9 EC PPy ethanol 0.3-0.4 10 EC PPy Ethylene glycol 0.5-0.6 11 EC PNIPAM water 0.3-0.4 12 EC PSS water 0.4 13 EC PAM water 12:25

• - EC-SPANI = exfoliated graphene, functionalized with sulfonated polyaniline,
• - EG-PANI = exfoliated graphene, functionalized with polyaniline,
• - EG-PPy = exfoliated graphene, functionalized with polypyrrole,
• - EG-PNIPAM = exfoliated graphene, functionalized with poly (N-isopropylacrylamide),
• - EG-PSS = exfoliated graphene, functionalized with poly (styrenesulfonate),
• - EG-PAM = exfoliated graphene, functionalized with poly (methylene-bis-acrylamide).

In one embodiment, only the outer layer of the two-dimensionally layered base material is exfoliated and functionalized, whereby the exfoliated and functionalized semiconductor or conductor material in the form of particles remains bound to the base material via an incompletely exfoliated edge portion of the particles such that the particles are scaly on the surface of the basic material.

The separation of the functionalized semiconductor or conductor material from the electrolyte solution is then carried out by removing it together with the base material from the electrolyte solution. It is advantageous to obtain a surface-functionalized base material.

Advantageously, the structural properties of the two-dimensionally layered base material can thus be retained, and the functionalized semiconductor or conductor material serves as surface functionalization on the base material.

Examples of such an embodiment include functionalized graphite foils and functionalized carbon fibers in which the functionalized material increases the surface area of the base material. These can be used, for example, as catalyst supports or as an enhancement of fiber-matrix interactions in carbon fiber reinforced composites.

The invention also relates to the use of the functionalized semiconductor or conductor material according to the invention for producing a dispersion in inorganic and / or organic liquid media.

For the purposes of the invention, inorganic and / or organic liquid media are understood as meaning both pure and multi-component solvents or monomers or silicones or mixtures thereof.

In one embodiment, the dispersion is free of interfacial tension modifying compounds such as surfactants, detergents or emulsifiers.

The invention also relates to the use of the functionalized semiconductor or conductor material according to the invention for producing a dispersion in aqueous and / or alcoholic solution.

Advantageously, the conductor or semiconductor material produced according to the invention has a particularly low defect density. Raman measurements show that the functionalization of the exfoliated material with small organic molecules or polymers protects the surface of the base material from oxygen radicals during exfoliation. This is evident by particularly low I _D -I _G ratios.

For example, EG-PANI produced according to the invention exhibits an I _D -I _G ratio of 0.12 or EG-PPy prepared according to the invention and an I _D -I _G ratio of 0.13.

The invention also provides the use of a functionalized semiconductor or conductor material produced by the process according to the invention in electronic components.

The invention also provides the use of a functionalized semiconductor or conductor material produced by the process according to the invention as an electrode material, for example in batteries or accumulators.

The invention also relates to the use of a functionalized semiconductor or conductor material according to the invention as a filler in resins and polymer solutions, such as paints, paints, adhesives and similar liquid formulations, such as lubricants.

The invention also provides the use of a functionalized semiconductor or conductor material according to the invention as a filler in composites such as polymer composites, metal matrix composites, ceramic composites and similar solid formulations, for example in the form of masterbatches.

For the realization of the invention, it is also expedient to combine the above-described embodiments according to the invention, embodiments and features of the claims in an expedient manner.
The following exemplary embodiments are intended to explain the invention in more detail, without, however, limiting it to:

list of figures

• 1: Schematische Illustration der in-situ Exfolierung und Funktionalisierung von Graphit,
• 2: Vorgeschlagener Mechanismus der in-situ Funktionalisierung,
• 3: RAMAN Spektren von a) EG und b) PPy-funktionalisiertem EG,
• 4: a) XPS Übersichtsspektren von EG und EG-PP_Y, b) hochaufgelöstes XPS-Spektrum der C1s-Region von EG, c) hochaufgelöstes XPS-Spektrum der C1s-Region von EG-PPY und d) hochaufgelöstes XPS-Spektrum der N1s-Region von EG-PPY,
• 5: RAMAN Spektrum von PANI-funktionalisiertem EG,
• 6: a) hochaufgelöstes XPS-Spektrum der C1s-Region von EG-PANI und b) hochaufgelöstes XPS-Spektrum der N1s-Region von EG-PANI,
• 7: a) TGA, b) AFM und c) RAMAN Analysen von SPANI-funktionalisiertem EG (EG-SPANI),
• 8: XPS Analyse von EG-SPANI: a) Übersichtsspektrum und hochaufgelöste XPS-Spektren b) der C1s-Region, c) der S2p-Region und d) der N1s-Region,
• 9: Schematische Illustration der Massenproduktion von EG-SPANI (= Exfoliertes Graphen, mit sulfoniertem Polyanilin funktionalisiert) durch ein Durchlaufsystem,
• 10: a) TGA und b) AFM Analysen von PNIPAM-funktionalisiertem EG (EG-PNIPAM),
• 11: XPS Analyse von EG-PNIPAM a) Übersichtsspektrum und b) hochaufgelöstes Spektrum der N1s-Region,
• 12: TGA Analysen von a) EG funktionalisiert mit Polymethylenbisacrylamid (PAM) b) EG funktionalisiert mit sulfoniertem Polystyrol,
• 13: a) TGA, b) XPS-Übersichtsspektrum und c) XPS N1s-Region Analysen eines Butylamin-funktionalisierten EG d) erhöhter Butylamin-Funktionalisierungsgrad nachgewiesen durch TGA,
• 14: a) TGA und b) XPS-Spektren von, mittels Valeriansäure, Pentyl-funktionalisiertem EG,
• 15: Vorgeschlagener Mechanismus für die direkte post-Funktionalisierung von EG unmittelbar nach der Exfolierung,
• 16: a, b) RAMAN und c) TGA Spektren von Polypyrrole-funktionalisiertem EG mittels direkter post-Funktionalisierung,
• 17: XPS Analyse von Polypyrrole-funktionalisiertem EG mittels direkter post-Funktionalisierung, a) Übersichtsspektrum, b) C1s-Region und c) N1s-Region,
• 18: TGA Analyse von EG nach direkter post-Funktionalisierung mit a) Valeriansäure, b) Butylamin und tert-Octylamin,
• 19: Zetapotential-Messungen wässriger Dispersionen funktionalisierter Graphene,
• 20: Ladungs- und Entladungskurve einer Halbzellen-Lithiumionenbatterie mit LiCoO₂/EG-SPANI (90/10) als Kathodenmaterial,
• 21: Zyklische Voltametrie Messungen von 3-Elektodenzellen Superkondensatoren mit einem freistehenden Film von funktionalisiertem Graphen (EG-SPANI) als Elektrode.

The present invention is described in more detail by the following figures and exemplary embodiments, without these being intended to limit the breadth of the claims defined above:

• 1 : Schematic illustration of the in-situ exfoliation and functionalization of graphite,
• 2 : Proposed mechanism of in-situ functionalization,
• 3 : RAMAN spectra of a) EG and b) PPy-functionalized EG,
• 4 : a) XPS overview spectra of EG and EG-PP _Y , b) high-resolution XPS spectrum of the C1s region of EG, c) high-resolution XPS spectrum of the C1s region of EG-PPY and d) high-resolution XPS spectrum of the N1s Region of EC-PPY,
• 5 : RAMAN spectrum of PANI-functionalized EC,
• 6 a) High-resolution XPS spectrum of the C1s region of EG-PANI and b) High-resolution XPS spectrum of the N1s region of EG-PANI,
• 7 : a) TGA, b) AFM and c) RAMAN analyzes of SPANI-functionalized EC (EC-SPANI),
• 8th : XPS analysis of EG-SPANI: a) overview spectrum and high-resolution XPS spectra b) of the C1s region, c) of the S2p region and d) of the N1s region,
• 9 : Schematic illustration of the mass production of EG-SPANI (= exfoliated graphene, functionalized with sulfonated polyaniline) by a continuous flow system,
• 10 : a) TGA and b) AFM analyzes of PNIPAM-functionalized EC (EG-PNIPAM),
• 11 : XPS analysis of EG-PNIPAM a) overview spectrum and b) high-resolution spectrum of the N1s region,
• 12 : TGA analyzes of a) EG functionalized with polymethylene bisacrylamide (PAM) b) EG functionalized with sulfonated polystyrene,
• 13 : a) TGA, b) XPS overview spectrum and c) XPS N1s region analyzes of a butylamine-functionalized EG d) increased butylamine functionalization level detected by TGA,
• 14 a) TGA and b) XPS spectra of, by means of valeric acid, pentyl-functionalized EG,
• 15 : Proposed mechanism for direct post-functionalization of EG immediately after exfoliation
• 16 : a, b) RAMAN and c) TGA spectra of polypyrrole-functionalized EG by direct post-functionalization,
• 17 XPS analysis of polypyrrole-functionalized EG by direct post-functionalization, a) overview spectrum, b) C1s region and c) N1s region,
• 18 : TGA analysis of EG after direct post-functionalization with a) valeric acid, b) butylamine and tert-octylamine,
• 19 : Zeta Potential Measurements of Aqueous Dispersions of Functionalized Graphenes,
• 20 : Charge and discharge curve of a half cell lithium ion battery with LiCoO ₂ / EG-SPANI (90/10) as the cathode material,
• 21 : Cyclic voltammetry measurements of 3-cell supercapacitors with a freestanding film of functionalized graphene (EC-SPANI) as an electrode.

Characterization of the produced materials

SEM images were obtained using a field emission scanning electron microscope (Gemini 1530 LEO) with an acceleration voltage of 10 keV. AFM characterization was performed on a Veeco Nanoscale Illa - Multimode Picoforce (Digital Instruments). Raman spectroscopy and mapping was performed on a Bruker RFS 100 / S spectrometer (laser wavelength 532 nm). The XPS analyzes were carried out on a Thermo Scientific K-alpha X-ray photoelectron spectrometer with a basic chamber pressure between ~ 10 ^-8 -10 ^-9 mbar and an Al anode as X-ray source (X-ray radiation of 1496 eV). Spot sizes of 400 μm were used. Overview spectra were recorded with an average of 10 scans, a pass energy of 200.00 eV and a step size of 1 eV. High-resolution spectra were recorded with an average of 10 scans with a lethal energy of 50.00 eV and a step size of 0.1 eV. The surface resistances of the EG films were measured with a four-point resistance measuring system using a Keithley 2700 multimeter (probe pitch: 0.635 mm, Rs = 4.532 V / L).

Embodiment 1

Electrochemical exfoliation and in situ functionalization of graphite with polypyrrole and preparation of a dispersion of polypyrrole-functionalized graphene (EG-PPy)

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate ( 0 , 1 M, 0.8 g) in 60 ml of deionized water. Pyrrole (7 μl, "Reagent Grade", 98% purity) was dissolved in 10 ml of water to obtain a 0.01 M monomer solution. After the electrodes were immersed in the electrolyte (6 cm ^{2 of} active electrode area in the solution), a constant potential of 10V In order to start the exfoliation process, at the same time the monomer solution was metered in at a rate of 20 ml / h by means of a syringe pump.

After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residues such as ammonium sulfate and pyrrole monomers. Subsequently, the light gray product (polypyrrole-functionalized graphene, EG-PPY, 60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The aqueous dispersion thus obtained contained graphene in a concentration of 0.1-0.2 mg / ml and was stable for one week, that is, there was no sedimentation of the particles.

For dispersions in other solvents, the product (polypyrrole-functionalized graphene, EG-PPY, 60 mg) after washing with water in, for example, ethanol or ethylene glycol (30 ml each) was similarly dispersed by mild sonication and allowed to stand for 24 hours. The supernatants thus obtained gave stable dispersions having a graphene content of 0.2-0.3 mg / ml (ethanol) and 0.5-0.6 g / ml (ethylene glycol).

The reaction was scaled up by using thicker graphite foils while maintaining the electrode area in the electrolyte and at elevated pyrrole concentration (in constant proportion to the weight of the graphite electrode).

The successful functionalization could be detected by X-ray photoelectron spectroscopy (XPS). There was an oxygen content of 11.46 at% for EG and 9.52 at% for EG-PPy.

In the case of EG-PPy, in contrast to EG, nitrogen was also detected in a concentration of 2.79 atom%, which belongs to the polypyrrole groups ( 4a) ,

The high-resolution spectrum of the N1s region ( 4d) shows a major band at 400 eV which can be assigned to the -NH groups, as well as a band at 401 eV which corresponds to the polaron structure (CN ⁺ ) of polypyrrole.

The high-resolution spectrum of the C1s region ( 4c) shows three major bands at 284.35 eV, 285.4 eV and 287.2 eV, which can be assigned to the C = C, C-OH and C = O bonds.

In contrast, unfunctionalized EGs show five different bands ( 4b) , In addition to the bands at 284.4 eV, 285.2 eV and 287.2 eV (C = C, C-OH and C = O bonds), two further bands occur at 286.5 eV and 290.2 eV, which epoxide (COC) and carboxylate groups (OC = O) are to be assigned ( , The absence of epoxide groups in the case of the functionalized EG shows that the graphene undergoes less strong oxidation during exfoliation, which is attributed to a protective effect of PPy functionalization of the basal plane.

The high quality of the functionalized graphene can be illustrated by means of RAMAN spectroscopy. While in the spectrum of EG a relatively high intensity ratio of the D and G peaks of 0.52 ( 3a) suggesting a significant degree of defect sites (by the attack of hydroxyl radicals on the exposed graphene surfaces), the addition of the 0.01M aqueous pyrrole solution during exfoliation can protect the graphene surface by the formed polypyrrole functionalities, indicated by a low I _D -I _G Ratio of 0.13 is clarified. ( 3b) ,

A thin film of EG-PPy was made by filtration of a dispersion on a PC filter paper. The film resistance of the film was determined using a four-point resistance measuring system and the layer thickness by means of SEM, from which a conductivity of approximately 500 S / cm was determined.

Zeta potential measurements of aqueous dispersions showed the stability of EG-PPy dispersions over a broad pH range ( 19 )

Embodiment 2

Electrochemical exfoliation and in situ functionalization of graphite with polyaniline and preparation of a dispersion of polyaniline-functionalized graphene (EG-PANI)

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.8 g) in 60 mL of deionized water. Aniline (10 μL, Acros organics, 99.8% pure) was dissolved in 26 μL H ₂ SO ₄ and 10 mL water to give a 0.01 M monomer solution. After the electrodes were immersed in the electrolyte (6 cm ^{2 of} active electrode area in the solution), a constant potential of 10V was applied to start the exfoliation process, while at the same time the monomer solution was metered in at a rate of 15 ml / h by means of a syringe pump.

After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residue, such as ammonium sulfate and aniline monomer. Subsequently, the light gray product (polyaniline-functionalized graphene, EG-PANI, 60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min sonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant was removed. The resulting aqueous dispersion contained graphene at a concentration of 0.1-0.2 mg / ml and was stable for one week.

For dispersions in other solvents, the product (polyaniline-functionalized graphene, EG-PANI, 60 mg) after washing with water, for example in ethanol or ethylene glycol (30 ml each) was dispersed by means of mild ultrasound treatment and allowed to stand for 24 h. The supernatants thus obtained gave stable dispersions having a graphene content of 0.2-0.3 mg / ml (ethanol) and 0.5-0.6 g / ml (ethylene glycol).

The reaction was scaled up by the use of thicker graphite sheets while maintaining the electrode area in the electrolyte and under increased aniline concentration (in constant proportion to the weight of the graphite electrode).

The successful functionalization could be detected by X-ray photoelectron spectroscopy (XPS).

The result was an oxygen content of 11.46 atom% for EG and 6.68 atom% for EG-PANI. In the case of EG-PANI, in contrast to EC, nitrogen was also detected in a concentration of 2.02 atom%, which is assigned to the polyaniline groups ( 6a . 6b) ,

The high-resolution spectrum of the N1s region ( 6b) Figure 3 shows three bands at 399eV, 400 eV and 401 eV which can be assigned to the C = N, -NH and -NH ⁺ groups of polyaniline.

The high-resolution spectrum of the C1s region ( shows three major bands at 284.4 eV, 285.2 eV and 286.5 eV, which can be assigned to the C = C, C-OH and C = O bonds while the proportion of epoxy groups is low.

The high quality and low defect density of the functionalized graphene can be demonstrated by means of RAMAN spectroscopy. By adding the 0.01M aqueous aniline solution during exfoliation, the graphene surface can be protected by the polyaniline functionalities formed, as illustrated by a low I _D -I _G ratio of 0.12. ( 5 ).

A thin film of EG-PANI was made by filtration of a dispersion on a PC filter paper. The film resistance of the film was determined by a four-point resistance measuring system and the layer thickness by means of SEM, from which a conductivity of approximately 400 S / cm was determined.

Zeta potential measurements of aqueous dispersions showed the stability of EG-PANI dispersions in the neutral pH range and a low stability under acidic conditions ( 19 )

Embodiment 3

Electrochemical exfoliation and in situ functionalization of graphite with sulfonated polyaniline and preparation of a dispersion of EG-SPANI (= exfoliated graphene, functionalized with sulfonated polyaniline)

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.8 g) in 60 mL of deionized water. Aniline sulfonic acid (18 mg, Sigma-Aldrich, 95% purity) was dissolved in 26 μL H ₂ SO ₄ and 10 mL water to obtain a 0.01 M monomer solution. After the electrodes were immersed in the electrolyte (6 cm ^{2 of} active electrode area in the solution), a constant potential of 10V was applied to start the exfoliation process, while at the same time the monomer solution was metered in at a rate of 15 ml / h by means of a syringe pump.

After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residue, such as ammonium sulfate and aniline monomer. Subsequently, the dark gray product (polyaniline sulfonate-functionalized graphene, EG-SPANI, 60 mg) was dispersed in deionized water (30 ml) by gentle sonication (30 min sonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The resulting aqueous dispersion contained graphene at a concentration of 0.3-0.4 mg / ml and was stable for over a week.

For dispersions in other solvents, the product (polyaniline sulfonate-functionalized graphene, EG-SPANI, 60 mg) was similarly dispersed after washing with water in, for example, ethanol or ethylene glycol (30 ml each) by mild sonication and allowed to stand for 24 hours. The supernatants thus obtained gave stable dispersions having a graphene content of 0.4-0.5 mg / ml (ethanol) and 0.8-1.0 g / ml (ethylene glycol).

The reaction was scaled up by the use of thicker graphite sheets while maintaining the electrode area in the electrolyte and under increased aniline concentration (in constant proportion to the weight of the graphite electrode).

The successful functionalization could be demonstrated by thermogravimetry (TGA), where the functionalized EC-SPANI showed a nearly 5 wt% higher mass loss compared to unfunctionalized EG ( 7a) ,

The AFM investigations showed a layer thickness of 4 nm or 1.2 nm for the edges and basal planes of the platelets ( 7b) , RAMAN measurements showed a low I _D / I _G ratio of 0.12 and thus a low defect density ( 7c) ,

By means of X-ray photoelectron spectroscopy (XPS) it was possible to detect a nitrogen content of 2.15 atomic% and a sulfur content of 0.62 atomic%, which are assigned to the polyaniline sulfonate groups ( 8a) ,

The high-resolution spectrum of the N1s region shows a major band at 400 eV which can be assigned to the -NH groups, as well as the band at 401 eV which is the polaron structure (CN ⁺ ) of polyaniline sulfonate. The high-resolution spectrum of the C1s region ( 8b) shows three major bands at 284.35 eV, 285.4 eV and 287.2 eV, which can be assigned to the C = C, C-OH and C = O bonds. The high-resolution spectrum of the sulfur region ( 8c) shows two bands at 167.4 eV and 168.6 eV which can be assigned to the sulfonic acid or sulfonate groups of the polyaniline sulfonate.

A thin film of EG-SPANI was made by filtration of a dispersion on a PC filter paper. The film resistance of the film was determined by means of a four-point resistance measuring system and the layer thickness by means of SEM, from which a conductivity of approximately 800 S / cm was determined.

Zeta potential measurements of aqueous dispersions showed the stability of EG-SPANI dispersions in a broad pH range (3-10) with a zeta potential of below -40 mV ( 19 )

Embodiment 4

Mass production of EG-SPANI (= exfoliated graphene, functionalized with sulfonated polyaniline) through a continuous flow system

The graphite finish was carried out in a continuous system using graphite foils (5 cm x 30 cm, 2.3 g per foil) (Alfa Aesar, 99.99% purity) as working anodes and copper foils of the same dimensions as cathodes. The copper electrodes were attached to the reactor wall, where the graphite electrodes are immersed in the electrolyte from above ( 9 ). The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 46.2 g), aniline sulfonic acid (1 g, Sigma-Aldrich, 95% purity) and 1.4 mL H ₂ SO ₄ in 3.5 L deionized water and flowing continuously through a constant speed pump into the system. After immersing the electrodes in the electrolyte (150 cm ^{2 of} active electrode area in the solution), a constant potential of 10V was applied to start the exfoliation and polymerization process.

After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated 3 times (2 L) to wash out any residue, such as ammonium sulfate and aniline monomer. Subsequently, the dark gray product (polyaniline sulfonate functionalized graphene, EG-SPANI, 2.2 g) was dispersed in deionized water (150 ml) by mild sonication (30 min, 30% amplitude, 2 watts). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The resulting aqueous dispersion contained graphene at a concentration of 0.5 mg / ml and was stable for a week.

Embodiment 5

Electrochemical exfoliation and in situ functionalization of graphite with poly-N-isopropylacrylamide and preparation of a dispersion of EG-PNIPAM (= poly-N-isopropylacrylamide-functionalized graphene)

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.8 g) in 60 mL of deionized water. N-isopropylacrylamide (30 mg, 0.25 mmol, Sigma, 97% purity) was dissolved in 10 mL of water to obtain a 0.02 M monomer solution. After the electrodes were immersed in the electrolyte (6 cm ² active electrode area in the electrolytic solution), a constant potential of 10V was applied to start the exfoliation process, while the monomer solution was metered in at a rate of 20 ml / hr by a syringe pump.

After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residue, such as ammonium sulfate and aniline monomer. Subsequently, the dark gray product (poly-N-isopropylacrylamide-functionalized graphene, EG-PNIPAM, 60 mg) was dispersed in deionized water (30 ml) by gentle sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The resulting aqueous dispersion contained functionalized graphene at a concentration of 0.3-0.4 mg / ml and was stable for over a week.

The successful functionalization could be demonstrated by TGA, where the functionalized EG-PNIPAM showed more than 40 wt% mass loss compared to unfunctionalized EG ( 10a) ,

The AFM studies showed a layer thickness of 3 nm, which illustrates the presence of functional groups on the surface ( 10b) ,

By means of X-ray photoelectron spectroscopy (XPS) it was possible to detect a nitrogen content of 0.86 atom% and an increase in the C / O ratio, which are attributable to the PNIPAM functionalization ( 11a) , The high-resolution spectrum of the N1s region shows a major band at 400 eV which can be assigned to the -NH groups, as well as the band at 401 eV which corresponds to the amide structure of PNIPAM ( 11b) ,

A thin film of EG-PNIPAM was made by filtration of a dispersion on a PC filter paper. The relatively high sheet resistance of the film of ~ 140 Ω / _□ (determined with a four-point resistance measuring system) is due to the presence of the PNIPAM insulator on the graphene surface.

The process was also successfully carried out in an analogous manner with other vinyl monomers, such as methylenebis-acrylamide and sodium 4-vinylbenzenesulfonate, which could be polymerized on the surface of the graphene. The successful functionalization with poly (methylene-bis-acrylamide) (PAM) and poly (sodium 4-vinylbenzenesulfonate) (PSS) was detected analogously to Example 4 by means of TGA ( 12a and 12b) ,

In addition, stable aqueous dispersions with EG-PAM (0.25 mg / ml) and EG-PSS (0.4 mg / ml) could be prepared.

Embodiment 6

Electrochemical exfoliation and in situ functionalization of graphite with butylamine

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.93 g) and butylamine (30 mg, 0.41 mmol, Aldrich, 99.5% purity) in 70 mL of deionized water. After immersing the electrodes in the electrolyte (6 cm ² active electrode area in the electrolyte solution), a constant potential of 10V was applied to start the exfoliation process. After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3 × 400 mL) to wash out any residue such as ammonium sulfate and butylamine. Subsequently, the dark gray product (60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The resulting aqueous dispersion contained functionalized graphene at a concentration of 0.1 mg / ml and was stable for one week.

In TGA measurements, a residual mass of 66 wt.% Was determined, the loss being due essentially to the cleavage of the butyl groups at 374 ° C ( 13a) ,

By means of X-ray photoelectron spectroscopy (XPS) it was possible to detect a nitrogen content of 1.11 atomic% which can be assigned to the butylamine groups ( 13b) , The high-resolution spectrum of the N1s region shows three main bands which can be assigned to the amide, amine and NH ₃ ⁺ groups ( 13c) ,

The degree of functionalization could be increased by increasing the butylamine concentration (150 mg, 2 mmol) under otherwise identical conditions as above. This could also be demonstrated by an increased mass loss in the TGA to a residual mass of 51 wt.% ( 13d) ,

The process was also successfully carried out in an analogous manner with other amines, such as tert-octylamine, melamine and 2-amino-2- (hydroxymethyl) -1,3-propanediol (TRIS).

Embodiment 7

Electrochemical exfoliation and in situ functionalization of graphite with valeric acid

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1M, 0.93g) and valeric acid (30 mg, 0.3 mmol, Alfa Aesar, 99% purity) in 70 mL of deionized water. After immersing the electrodes in the electrolyte (6 cm ² active electrode area in the electrolyte solution), a constant potential of 10V was applied to start the exfoliation process.

After the exfoliation was completed and the graphite foil was consumed, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residues such as ammonium sulfate and valeric acid. Subsequently, the dark gray product (60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The aqueous dispersion thus obtained contained graphene at a concentration of 0.1 mg / ml and was stable for one week.

The successful functionalization could be demonstrated by TGA, where the functionalized EG showed a 4 wt.% Greater mass loss compared to unfunctionalized EG ( 14a) ,

At the same time, X-ray photoelectron spectroscopy (XPS) showed an increase in the C / O ratio to ~ 9 (compared to unfunctionalized EG: -7.3) ( 14b) which can be explained by the attack and the functionalization with pentyl radicals to the graphene surface ( 2 ).

Embodiment 8

Electrochemical exfoliation of graphene and subsequent functionalization with polypyrrole

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm × 3 cm, 100 mg per film) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.93 g) in 70 mL of deionized water. After immersing the electrodes in the electrolyte (6 cm ² active electrode area in the electrolyte solution), a constant potential of 10V was applied to start the exfoliation process.

After the exfoliation was complete and the graphite foil was consumed, pyrrole (100 μl, 1.5 mmol, Sigma-Aldrich, 98% purity) was added and the mixture was homogenized for 5 min in an ultrasonic bath and then stirred for 30 min. Subsequently, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residue, such as ammonium sulfate and pyrrole. Subsequently, the dark gray product (60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant dispersion was removed. The resulting aqueous dispersion contained functionalized graphene at a concentration of 0.2 mg / ml and was stable for one week.

The proposed mechanism for direct functionalization is in 15 shown. The process of electrochemical exfoliation contains free radicals on the surface of the EC, which are stabilized by the extended network of conjugated electrons ( 15b) , These free radicals and anions can be used as starting points for free-radical and oxidative polymerization reactions to covalently functionalize the graphene surface. Another possible mechanism is the activation of oxygen-containing groups (in epoxide) on the graphene surface by electrochemical exfoliation ( 15b) ,

The RAMAN spectrum showed an I _D / I _G ratio of 0.3. In addition, the RAMAN spectrum indexed three bands at 848.5 cm ^-1 , 994.9 cm ^-1 and 1050.1 cm ^-1 ( 16a) , which can be attributed to the functionalization of EG with polypyrrole (EG-PPy) and are not observed in unfunctionalized EC ( 16b)

In addition, the successful functionalization by TGA could be demonstrated, where the functionalized EG showed a 19 wt.% Higher mass loss compared to unfunctionalized EC ( 16c) ,

XPS measurements showed an oxygen content of 10.92 at% (EC) and 8.43 at% (EG-PPy) as well as a 3.37 at% nitrogen for EG-PPy due to the polypyrrole functionalization ( 17a)

The high-resolution spectrum of the N1s region shows a major band at 400 eV which can be assigned to the -NH group as well as the band at 401 eV which corresponds to the polaron structure (CN ⁺ ) of polypyrrole ( 17c) , The high-resolution spectrum of the C1s region ( 17b) shows a band at 285.5 eV associated with the CN bond which is undetectable in unfunctionalized EG.

Embodiment 9

Electrochemical exfoliation of graphene and direct functionalization with valeric acid

By the effects of electrochemical exfoliation on the surface of graphene and the generation of active / reactive centers (see 15 In addition, the surface can be functionalized with various other agents, for example containing amine or carboxylate groups, as will be illustrated in the following example.

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were placed parallel to the graphite electrodes at a fixed distance of 2 cm. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.93 g) in 70 mL of deionized water. After immersing the electrodes in the electrolyte (6 cm ² active electrode area in the electrolyte solution), a constant potential of 10V was applied to start the exfoliation process.

After the exfoliation was completed and the graphite foil was consumed, valeric acid (100 mg, 0.98 mmol, Alfa-Aesar, 99% purity) was added and the mixture was homogenized for 5 min in an ultrasonic bath and then stirred for 30 min. Subsequently, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3x400 mL) to wash out any residue, such as ammonium sulfate and pyrrole. Subsequently, the dark gray product (60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant was removed. The aqueous dispersion thus obtained contained graphene at a concentration of 0.1 mg / ml and was stable for one week.

The successful functionalization was demonstrated by TGA, where the functionalized EG showed a residual mass of nearly 63 wt.% Compared to unfunctionalized EG.

In addition, the level at about 200 ° C, which is usually assigned to the conversion of epoxy groups is significantly weaker than in unfunctionalized EG, which indicates a reaction between the epoxy groups in EG and the valeric acid ( 18a) ,

Embodiment 10

Electrochemical exfoliation of graphene and direct functionalization with amines

The graphite finish was carried out in a two-electrode system using graphite foils (2 cm x 3 cm, 100 mg per foil) (Alfa Aesar, 99.99% purity) as working anodes and gold foils of the same dimensions as cathodes. The gold electrodes were parallel to the graphite electrodes with a solid Spaced 2 cm apart. The electrolyte for exfoliation was prepared by dissolving ammonium sulfate (0.1 M, 0.93 g) in 70 mL of deionized water. After the electrodes were immersed in the electrolyte (6 cm ² active electrode area in the electrolyte) a constant potential of 10V was applied to start the exfoliation process.

After the exfoliation was completed and the graphite foil was consumed, butylamine (100 mg, 1.37 mmol, Sigma-Aldrich, 99.5% purity) was added to the electrolyte and the mixture was homogenized for 5 min in an ultrasonic bath and then stirred for 30 min. Subsequently, the suspended graphene flakes were separated on a 0.2 μm PC (polycarbonate) filter and washed with deionized water. The washing process was repeated three times (3 × 400 mL) to wash out any residue such as ammonium sulfate and pyrrole. Subsequently, the dark gray product (60 mg) was dispersed in deionized water (30 ml) by mild sonication (30 min. Ultrasonic bath). This dispersion was allowed to stand for 24 hours to sediment non-exfoliated non-functionalized platelets and larger particles. Subsequently, the supernatant was removed. The aqueous dispersion thus obtained contained graphene at a concentration of 0.1 mg / ml and was stable for one week.

The successful functionalization could be detected by TGA. In 18 a It can be seen that the step at about 200 ° C, which is usually assigned to the conversion of epoxy groups is significantly weaker than in unfunctionalized EC. This indicates a reaction between the epoxy groups in EG and the butyl amine. In an analogous manner, the functionalization with tert-octylamine was detected by TGA ( B) ,

Embodiment 11

Functionalized graphene powder as cathode additive in lithium-ion batteries

Functionalized graphene (EG-SPANI) was added as a conductive additive to typical cathode materials such as LiFePO ₄ and LiCoO ₂ in a solution-mixing method to produce electrodes for lithium-ion batteries.

This was the embodiment according to 3 prepared dispersion with commercially available cathode material (LiFePO ₄ / LiCoO ₂ ) in the mass ratio of 1: 1 mixed with the use of ultrasound. After filtration and drying of the mixture, it was filled as a cathode material in a half-cell, was arranged in the lithium foil as an anode.

At a constant flow rate of 0.1 C (1C = 170 mAh / g) the material showed a loading and unloading capacity of 120 mAh / g ( 20 ).

Embodiment 12

Functionalized graphene as freestanding electrode films Supercapacitor cells

Freestanding films of functionalized graphene (EG-SPANI) were used as electrode in a 3-electrode supercapacitor cell, with platinum wire as counter electrode, AgCl as reference electrode and 0.1 M sulfuric acid as electrolyte. The functionalized graphenes showed a good capacity of up to 312 F / g, while unfunctionalized EG had a capacity of less than 20 F / g ( 21 ).

QUOTES INCLUDE IN THE DESCRIPTION

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Claims (10)

Process for the production of functionalized semiconductor or conductor material from a layered base material by electrolytic exfoliation, in an electrolysis cell, comprising at least one electrode pair of first and second electrodes, and an aqueous and / or alcoholic electrolyte solution containing sulfuric acid and / or at least one salt, selected from sulphate and / or hydrogen sulphate and / or perchlorate and / or persulphate salt, with the steps: d) contacting the electrodes with the electrolyte solution, e) electrolytic exfoliation of the base material by applying a voltage between the first and second electrodes, f) separating the functionalized conductor or semiconductor material from the electrolyte solution, wherein at least the first of the electrodes of the electrode pair contains the layered carbon-based base material, wherein the first electrode is connected as an anode, wherein at least one organic compound is added to the electrolyte solution before and / or during or immediately after the electrolytic exfoliation Organic compound is selected from i. Anodically oxidizable organic molecules containing at least one alcohol and / or at least one amino and / or at least one carboxyl group and / or ii. organic molecules containing at least one isocyanate and / or at least one halide and / or at least one epoxy and / or at least one diazonium and / or at least one peroxide and / or at least one azido group and / or cyclic esters and / or cyclic Amides and / or iii. Precursors or monomers of electrically conductive polymers and / or iv. free radically polymerizable, water-soluble vinyl monomers which have in their structure at least one amino group and / or at least one anionic functional group. Method according to Claim 1 , characterized in that the semiconductor or conductor material is selected from graphene, graphene derivatives, carbon-based semiconductor or ladder polymers and / or layered chalcogenides of the general formula MQ ₂ , where M = Ti, Zr, Hf, V, Nb , Ta, Mo or W and where Q = O, S, Se or Te. Method according to Claim 1 or 2 , characterized in that the two-dimensionally layered structured base material is selected from semiconductive or conductive carbon modifications, carbon-based semiconductor or conductor polymers in the form of two-dimensionally structured base material and / or layered chalcogenides. Method according to one of Claims 1 to 3 , characterized in that the second electrode comprises a metal. Method according to one of Claims 1 to 4 , characterized in that the voltage is 1 to 20 volts. Method according to one of Claims 1 to 3 , characterized in that the precursors or monomers are selected from aromatic amines, aniline, pyrrole, thiophene and / or their derivatives. Method according to one of Claims 1 to 6 , characterized in that the functionalized material is dried and / or dispersed after the separation. Method according to one of Claims 1 to 6 , characterized in that the exfoliated and functionalized semiconductor or conductor material remains connected in the form of particles via a not completely exfoliated edge portion of the particles with the base material Use of a functionalized semiconductor or conductor material prepared by a method according to any one of Claims 1 to 7 for the preparation of a dispersion in inorganic and / or organic liquid media. Use of a functionalized semiconductor or conductor material prepared by a method according to any one of Claims 1 to 8th in electronic components and / or as electrode material and / or as Filler in resins and / or polymer solutions and / or as a filler in polymer composites, Metallmatrixkompositen and / or ceramic composites

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